Model Output Discussion - Winter arrives

[Mike Poole]

1 hour ago, mb018538 said:

Last night's ECM update shows the blocking signals of the last couple of ECM updates have gone now, and we're left with a sea of +NAO right through December.

With no zonal wind weakening forecast either, we could be seeing December end up being what autumn should have normally been?

You could also read that chart as an increasing signal for a Scandi high.  

[mountain shadow]

1 hour ago, mb018538 said:

Looks muted or non existent to me Nick. Don't think we will get any help from the MJO in this instance...

Yes, thought that might happen. Any proper cold courtesy of a Greenland or Scandi high is very low probability now.

[Methuselah]

I think most impacts from Storm Arwen will be from wind and storm surge; problems due to snowfall will be from heavy, sticky, wet stuff bringing down power lines? So, overall, a nasty weekend is in store!

    

Edited November 26, 2021 by Ed Stone
Charts are now TODAY'S!

[Midlands Ice Age]

17 minutes ago, Ed Stone said:

I think most impacts from Storm Arwen will be from wind and storm surge; problems due to snowfall will be from heavy, sticky, wet stuff bringing down power lines? So, overall, a nasty weekend is in store!

    

Pete

Those charts are yesterdays!!

MIA

 

[Battleground Snow]

Could be another near miss for a scandi high here on the 06z GFS?

[Methuselah]

I like those possible developments away to our northeast. I'd bet against real cold getting here this early. But, all the same, those T850s look very, very tasty!

     

Edited November 26, 2021 by Ed Stone

[SLEETY]

could be full on scandi high developing .Exciting times ahead

[Radiating Dendrite]

It certainly looks like a cool and seasonal start to December. I think the fact that every run now is pushing forwards a possible Scandi high theme is a big positive. Certainly enough cold around this year compared to past years. 

[mb018538]

Too much energy firing across the Atlantic now. Looks pretty flat to me in our neck of the woods out into December.

[Updated_Weather]

MetO have now issued a rare red wind warning for NE Scotland and NE England.. and further wind and snow warnings. Messy weekend folks!

[Cleeve Hill]

Haven’t seen a proper Scandi High for years. When would have been the last time I wonder?

Scandi highs and undercutting lows are a winter dream.

I recall in the early 80’s plenty of these in Bristol/Glos area and lots of snow days.

[Battleground Snow]

Control having a go too, and the mean just starting to pick it up, however very weak signal this far out.

Edited November 26, 2021 by Battleground Snow

[mb018538]

9 minutes ago, Updated_Weather said:

MetO have now issued a rare red wind warning for NE Scotland and NE England.. and further wind and snow warnings. Messy weekend folks!

It actually looks very dangerous now. I think somewhere will see winds in excess of 90mph, which is crazy for a northerly.....don't think I've ever seen it?

[Updated_Weather]

Just now, mb018538 said:

It actually looks very dangerous now. I think somewhere will see winds in excess of 90mph, which is crazy for a northerly.....don't think I've ever seen it?

Yep don’t think I’ve seen this either.. wouldn’t want to witness it well I would, just hope people keep safe!

[Bogman]

On 26/11/2021 at 11:49, Updated_Weather said:

Yep don’t think I’ve seen this either.. wouldn’t want to witness it well I would, just hope people keep safe!

Yep, totally agree mate.

[Ali1977]

2 minutes ago, Battleground Snow said:

Control having a go too, and the mean just starting to pick it up, however very weak signal this far out.

And the ENS 

[Dennis]

it seems it comes to a special wind/snow event into saturday 

[Climate Man]

13 minutes ago, Updated_Weather said:

Yep don’t think I’ve seen this either.. wouldn’t want to witness it well I would, just hope people keep safe!

October 1987 for one but yes very rare. 

[Ice Day]

2 minutes ago, Climate Man said:

October 1987 for one but yes very rare. 

If this storm develops as forecasted, it does have the potential to match the October 1987 'Great Storm' in wind speed. However, much of the damage from the '87 storm was due to the trees being in full leaf, so being 5 weeks later, we do have that in our favour this time around. Make no bones about though, this is an exceptional event, coming from the north as it is. 

[MATTWOLVES 3]

Firstly folks,wherever you are,especially those in the highest risk areas...PLEASE TAKE CARE..if your out and about,be even more vigilant! These conditions can kill,so don't for one minute understate them.

Secondly some promising signs from the 6z ens..quite a few ideas floating about,but nothing that says any specific pattern is certain.

And as above....if you can try and stay home.

Have a wonderful Weekend of weather watching.

[Updated_Weather]

19 minutes ago, Climate Man said:

October 1987 for one but yes very rare. 

I wasn’t born until 9 years later so definitely wouldn’t know that!

[sheikhy]

14 minutes ago, MATTWOLVES said:

Firstly folks,wherever you are,especially those in the highest risk areas...PLEASE TAKE CARE..if your out and about,be even more vigilant! These conditions can kill,so don't for one minute understate them.

Secondly some promising signs from the 6z ens..quite a few ideas floating about,but nothing that says any specific pattern is certain.

And as above....if you can try and stay home.

Have a wonderful Weekend of weather watching.

These charts remind me of the ec46 update that you posted on monday i think with all those scandi heights into december!!maybe the one last night lost the plot lool!

[Cold Winter Night]

Interesting to see that GFS/GEFS is picking up the idea of Scandi heights more and more.

One way of looking at the output is by the climatological regime chart.
It shows if, and how much the EPS output corresponds to one of the four defines regimes, which are broad Atlantic/European patterns.
Perhaps good to reiterate once in a while, those four regimes are Positive NAO (NAO+), Negative NAO (NAO-), Positive Blocking (BLO+) and Negative Blocking (BLO-). They are also depicted on the clusters by those coloured borders.

NAO+ is the generally zonal pattern, dreaded by coldies, bringing mild, wet gales.
NAO- in good shape is the Greenland High, with possible Arctic Northerlies for us.
BLO+ is the Scandinavian High (it can be a bit more the South though), with chances of a very cold and dry Easterly or Northeasterly.
BLO- or Anti-Blocking is the opposite: a trough over Scandinavia, into Europe, associated with an amplified Atlantic (Atlantic Ridge), we are in this pattern right now.

The regime chart is square, with the upper half representing BLO+, the lower half BLO-, the left hand side stands for NAO- and the right hand side for NAO+. Coldies prefer the regimes to move in the upper left triangle, mildies prefer it to dwell to the right.
The farther from the middle, the more pronounce the pattern is.

The 0z charts are below, from yesterday and today.
We do see a slow move from NAO- to NAO+, but the projection remains very close to the centre, therefore the regimes are not very pronounced in the output out to +192h.
Compared to yesterday, there is also some tendency to move from Anti-blocking to Blocking, removing the Scandi/Euro trough.

Let's be cautious to connect firm conclusions to that, but the move to Atlantic driven weather, although present, seems too weak to fear an endless mild onslaught throughout December, and the EPS leaves room for the GEFS Scandi height options.

[Methuselah]

A bit of a messy GEFS temperature ensemble today. I'm guessing the scatter relates to whether or not a Scandi HP will develop, and should one develop, how much if any impact it might have?

    

Edited November 26, 2021 by Ed Stone

[throwoff]

Major storm incoming.

Decent chance for nearly the entire country to see falling snow

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